基于快速应力释放的深埋隧洞岩爆防治对策研究

Research on prevention measures of rock burst based on rapid stress release in deep tunnel

大型地下工程开挖中,高地应力环境下高储能脆性岩体通常会通过脆性破裂快速释放应变能而产生岩爆。岩爆作为常见的一类动力失稳地质灾害现象,极大地威胁着现场施工人员和设备的安全。作为雅砻江锦屏二级水电站的主要工程,千米级埋深的引水隧洞也面临高地应力下硬岩岩爆问题。针对锦屏二级引水隧洞岩爆的特点,提出采用快速应力释放的方法防治岩爆,并采用数值模拟的方法优选了倾斜辐射爆破孔方案。数值模拟结果表明:该方法能使岩体内的初始应力快速卸荷,同时使应力集中区向岩体深部转移。通过在锦屏二级引水隧洞工程中的试验与运用,采用声波测试法对实施快速应力释放方案的效果进行检验,验证了快速应力释放方法防治岩爆的有效性。研究成果为解决类似工程岩爆防治问题提供了理论依据和借鉴。

Brittle rock mass generally reserves high strain energy under high ground stress condition.As it is excavated,rock burst will take place as a rapid release of the reserved strain energy.The rock burst is a hackneyed type of power unstable geologic hazard,which immensely threatens the builder and equipment safety.As a major construction of the Jinping II hydropower station on the Yalong River,deep water transfer tunnels face the problems of rock burst in hard rock under high geostress.According to the characteristic of the rock burst in Jinping II hydropower station,the method of preventing the rock burst by rapid releasing stress is put forward;and the scheme of inclined radiation blasting hole is selected through numerical simulation.The numerical simulation results show that the method can make the initial stress of rock mass rapid unloaded and the stress concentration area transferred to the deep place of rock mass.Through the testing and application in water transfer tunnels of Jinping II hydropower station,sonic wave testing has been applied to verify the effect of rapid stress releasing scheme;it turns out that the method of preventing the rock burst by rapid stress releasing is validated.The research results provide theoretical foundation and ways for preventing the rock burst in similar projects.